It’s not what you say but the way that you say it. I just came across this short video that illustrates the point rather nicely (along with multiple meanings of ‘whatever’).
Here the issue was predominantly pronunciation – or intonation to be specific. I think it’s a nice illustration of how meaning is not just conveyed with words. So much more is involved.

A lot of the English courses I write come with audio CDs, so periodically I spend a day or two in studios listening to actors performing for the recordings. When I lived in the UK, the American actors often sounded ultra-polite. It seemed over the top for my British ear so I was always asking if they could tone down the upbeat-and-perky and sound a bit more matter of fact.